Over the last decade there has been a virtual revolution of our understanding of the neoplastic process. The factors which regulate the malignant phenotype are discrete and limited in number. In many circumstances, malignant growth represents usurpation of normal cellular growth control signals. Thus, much information garnered from endocrinology (e.g., work on EGF, the insulin-like growth factors and platelet-derived growth factor) has major applicability to cancer. Furthermore, many of these growth regulatory processes are potential sites of immunologic and pharmacologic intervention. Antibodies against growth factors and their receptors already have shown promise in antitumor therapy. The development of growth factor analogs with antagonistic activity and the introduction of genetic information encoding antisense RNA for specific growth factors have also been associated with antitumor effects. The time is right for reviewing the process of neoplastic cell growth reputation in an open forum in which a variety of academic and industrial scientists can summarize current developments and explore new discoveries for improved cancer therapy. This meeting is being held in parallel with a meeting on "Steroid Hormone Action" and joint sessions will consider the relationship between steroid hormones and cancer as well as a joint session on "Transcriptional Control Mechanisms and Control of Development.